This invention relates to a collapsible stroller chassis which has two laterally arranged scissor frameworks, which form a top part, and a substructure, which bears the wheel axles.
The stroller chassis of the type in question is known in a large number of configurations. Also arranged on the stroller chassis is a push bar which, in the normal use state, is locked. If it is intended, however, for the stroller to be transported in the empty state, the stroller chassis is collapsed. For this purpose, first of all the push bar has to be unlocked and pivoted beyond the stroller chassis. If spring elements are used for this purpose, these are subject to wear. The substructure is arranged resiliently in relation to the top part. During the collapsing operation, the spacing between the two axles increases, this resulting in the collapsed assembly being relatively long. Moreover, the lateral stability of the stroller chassis is not satisfactory.
In the case of the prior-art constructions, the top part can move in relation to the substructure, albeit within relatively narrow limits. This has an adverse effect on comfort when the stroller is on the move.
An object of the invention is to configure a stroller chassis of the type described in detail in the introduction such that, while maintaining the smallest possible dimensions in the collapsed state, the lateral stability is increased in order to increase the comfort when the stroller is on the move.
This object is achieved in that the substructure and the facing ends of the scissor arms of the scissor framework are connected to one another by articulations such that, at least in the erected state of the top part, a rigid structural unit, is formed by the substructure and by the top part.
By virtue of the rigid structural unit, the lateral stability of the stroller chassis, and thus the comfort when the stroller is on the move, is increased to a considerable extent. Since, as with prior art strollers, the substructure and the top part are connected by movable elements, there will be the usual play or slackness between the various elements. The term xe2x80x9crigid structural unitxe2x80x9d is used herein to include structural units in which some movement between the structural elements is permitted by such play and/or interengage slackness. The articulations are designed such that, for collapsing and for erecting the top part, there is no need to overcome any significant frictional forces. However, the articulations are designed so as to compensate for the increasing spacings between the bottom ends of the scissor arms during the operation of collapsing the stroller chassis. Since the spacing between the wheel axles then no longer changes, the amount of space required in the collapsed state is reduced since the collapsed assembly is shorter than the configurations which have been known up until now. Moreover, the operation of loading an automobile trunk is made easier. Moreover the substructure has a frame, and the wheel axles are secured by means of resilient bearing blocks on those members of the frame which run parallel to, and are spaced apart from, the wheel axles. As a result of the resilient bearing blocks, the wheel axles are arranged resiliently in relation to the substructure. In order to compensate for the increase in the spacing between the bottom ends of the scissor arms during the operation of collapsing the stroller chassis, the articulations are mounted pivotably on the substructure, and each of the scissor arms is pivotally mounted on the opposite end region of a respective articulation. The articulations expediently comprise two side parts which are connected to one another by at least one central crosspiece located on the side directed away from the scissor arms. The necessary movements of the articulations and of the scissor arms are made possible as a result. Each articulation is expediently a single-piece molding, since this reduces the production costs.
For reasons of safety, a certain spacing between the wheel axles is necessary in order to prevent, for example, tilting. A compact, material-saving configuration is achieved if the wheel axles are arranged on the mutually remote sides of the two frame members of the substructure running parallel thereto. The dimensions of the frame of the substructure can then be minimized, the necessary spacing between the wheel axles being provided. When the stroller is placed on a horizontal surface, the frame is likewise located horizontally. At least the members which run parallel to, and are spaced apart from, the wheel axles are located level with the wheel axles or are offset a little way upwards. The bearing blocks are expediently configured in two parts. The two parts for each bearing block may then be connected firmly to one another by screws. The bores for securing the wheel axles are designed such that the wheel axles are clamped firmly. As, in the prior art, the stroller chassis is secured in its erected state by means of locking means on the push bar (handle). The articulations are expediently mounted on those members of the frame which are located transversely to the wheel axles. This distributes the load over the various members of the frame. The bearing blocks are designed for resilient connection to the substructure or the frame.